New methods to separate artifacts from normal and defective breathing patterns in different sleep-states, if infants are monitored at home.

Respiratory and cardiac monitoring was undertaken in the home for seven months in an infant at increased risk for cot-death (SIDS). The infant was a surviving non-identical twin of a SIDS sibling. In hospital, clinical and cardio-respiratory studies during sleep were normal. Analysis of eleven 24-hour tape-recordings showed that many of the alarms at home were the result of technical problems. Suspected apnoeas were identified initially from an oscilloscopic display of the original waveforms and from a compressed-record and histogram of the computed breath-to-breath intervals. Expanded pen-recordings confirmed some, but not all, of these suspected apnoeas (greater than 15s). The results indicate (i) the importance of verifying apnoeic episodes; (ii) the value of 24-h compressed recordings for identifying and timing the sleep cycles and their possible relationships to breathing defects; (iii) the need for improved instrumentation; (iv) the dangers of evaluating clinical prognosis or research from parental diaries.